package problems;

import interfaces.EulerProblemInterface;

import java.util.LinkedList;
import java.util.List;

import utility.ProblemSpecifics;

public class EulerProblem008 implements EulerProblemInterface {

	private static final String INPUT_SEQUENCE = "7316717653133062491922511967442657474235534919493496983520312774506326239578318016984801869478851843858615607891129494954595017379583319528532088055111254069874715852386305071569329096329522744304355766896648950445244523161731856403098711121722383113622298934233803081353362766142828064444866452387493035890729629049156044077239071381051585930796086670172427121883998797908792274921901699720888093776657273330010533678812202354218097512545405947522435258490771167055601360483958644670632441572215539753697817977846174064955149290862569321978468622482839722413756570560574902614079729686524145351004748216637048440319989000889524345065854122758866688116427171479924442928230863465674813919123162824586178664583591245665294765456828489128831426076900422421902267105562632111110937054421750694165896040807198403850962455444362981230987879927244284909188845801561660979191338754992005240636899125607176060588611646710940507754100225698315520005593572972571636269561882670428252483600823257530420752963450";
	private static final int NUMBER_OF_FACTORS_IN_PRODUCT = 5;
	private static final int NEUTRAL_ELEMENT_OF_MULTIPLICATION = 1;
	private ProblemSpecifics problemSpecifics;
	private List<Integer> input;
	private int maxProduct;
	private int currentProduct;

	public EulerProblem008() {
		String problemStatement = "Find the greatest product of five consecutive digits in the given 1000-digit number.";
		problemSpecifics = new ProblemSpecifics(problemStatement);
		input = produceListOfIntFromStringOfDigits(INPUT_SEQUENCE);
		maxProduct = 0;
		resetCurrentProduct();
	}

	// TOTO refactor me
	public void solve() {
		for (int i = 0; i < input.size() - NUMBER_OF_FACTORS_IN_PRODUCT; i++) {
			resetCurrentProduct();
			computeProductStartingFromIndex(i);
			updateMaxProduct();
		}
		problemSpecifics.setResultAndMarkSolved(maxProduct);
	}

	private void updateMaxProduct() {
		if (currentProduct > maxProduct) {
			maxProduct = currentProduct;
		}
	}

	private void computeProductStartingFromIndex(int currentIndex) {
		for (int j = 0; j < NUMBER_OF_FACTORS_IN_PRODUCT; j++) {
			currentProduct = currentProduct * input.get(currentIndex + j);
		}
	}

	private void resetCurrentProduct() {
		currentProduct = NEUTRAL_ELEMENT_OF_MULTIPLICATION;
	}

	private List<Integer> produceListOfIntFromStringOfDigits(
			String inputSequence) {
		List<Integer> inputList = new LinkedList<Integer>();
		for (int i = 0; i < inputSequence.length(); i++) {
			char characterFromSequence = inputSequence.charAt(i);
			int intFromChar = Character.getNumericValue(characterFromSequence);
			inputList.add(intFromChar);
		}
		return inputList;
	}

	public long reportResult() {
		return problemSpecifics.reportResult();
	}

	public ProblemStatus reportStatus() {
		return new ProblemStatus(problemSpecifics.isSolved());
	}

	public String stateTheProblem() {
		return problemSpecifics.stateTheProblem();
	}
}
